10G THE NAUTILUS. 



Genus CreneUa Brown, 1827. 

 There are five species, one of which inhabits New England. 



20G. Crenella yrandula, Tottc-n. 



Syn : Modiola ylandula Tott. GUI.; Mytilus decussatus Stimp.; 

 CreneUa decussatus Forbes & Hanley, DeKay. 



Shell small, thin, rounded oval ; beaks small, separated at the an- 

 terior end, and at one half the height of the shell ; surface with 

 minute lines of growth, crossed by numerous fine radiating ribs 

 which increase in number as they recede from the beaks; epidermis 

 brownish-yellow ; interior pearly ; margins sharp and crenulated. 

 Length one quarter of an inch, height nine-twentieths, breadth 

 three-tenths, 



This species was discovered by Col. Joseph G. Totten in Province- 

 town Harbor, and described in Silliman's Journal, Vol. xxvi, p. 367, 

 1834. It inhabits sandy and soft mud in water from 3 to 60 

 fathoms, from Sandy Hook to the Gulf of St. Lawrence, and is often 

 found in the stomachs of fishes. It has been dredged in various 

 places between these points, such as Buzzard's Bay, Vineyard 

 Sound, off Block Island, in Massachusetts Bay, Casco Bay and Bay 

 of Fundy. It is found fossil at- Montreal. 



Genus Modiolaria Gray, 1872. 



The shells of this genus are small, rhomboidal in shape, and are 

 sculptured by two series of radiating lines, one at each end, leaving 

 a smooth spate between. 



207. Modiolaria discors Linne. 



Syn : Mytilus discors Linn., Loven, Stimp., Hanley, etc.; Mytilus 

 discrepans Mont., Dill., Turt., Flem.; Modiola discrepans Lam., 

 Forbes, Gld., Migh., DeKay.; CreneUa discors Gray, Adams, Forbes 

 and Hanley; Modiolaria discors Loven, Binney, Dall, etc. 



Shell obliquely-oval, beaks near the anterior end ; surface coarsely 

 marked by lines of growth and divided into three fan-shaped spaces, 

 the anterior portion with eight fine lines radiating from the beaks to 

 the basal margin, the middle portion smooth and the posterior with 

 numerous lines radiating in an opposite direction from those on the 

 anterior end of the shell ; interior silvery. Length one inch, height 

 thirteen-twentieths, breadth two-fifths. 



Circumpolar : from Greenland to Long Island ; from Finmark to 

 Great Britain ; Bering's Straits to Puget Sound. Inhabits from 



